JP2018040035A - Process for treating lithium-ion battery scrap - Google Patents

Abstract

When leaching lithium-ion battery scrap containing copper, the processing of the lithium-ion battery scrap can reduce the load in the subsequent process by leaving copper as a solid without dissolving it in an acidic solution as much as possible. Provide a method. A method for treating lithium ion battery scrap according to the present invention includes a leaching step of leaching lithium ion battery scrap by bringing a lithium ion battery scrap containing at least copper into contact with an acidic solution and leaching the lithium ion battery scrap. At the timing when the oxidation-reduction potential (ORPvsAg / AgCl) of the acidic solution starts to rise rapidly, a metal piece containing at least one element of iron, nickel and cobalt is added to the acidic solution. [Selection] Figure 1

Description

  The present invention relates to a method for treating lithium ion battery scrap, and in particular, proposes a technique that can be used effectively for recovering valuable metals from various lithium ion battery scraps.

Lithium ion batteries used in many industrial fields, including various electronic devices, use lithium metal salts containing manganese, nickel and cobalt as positive electrode active materials. Along with the increase and the expansion of the range of use, the amount discarded due to the product life of the battery and defects in the manufacturing process is increasing.
Under such circumstances, it is desirable to easily recover the above-described expensive elements such as nickel and cobalt from lithium ion battery scraps that are discarded in large quantities at a relatively low cost for reuse.

  In order to process lithium ion battery scrap for recovering valuable metals, first, for example, powdery or granular lithium ion battery scrap obtained through various processes such as roasting, crushing and sieving as required. Is leached with aqueous hydrogen peroxide, and lithium, nickel, cobalt, manganese, iron, copper, aluminum, and the like that can be contained therein are dissolved in the solution to obtain a solution after leaching.

  Next, a solvent extraction method is performed on the leached solution to separate each metal element. Here, in order to separate each metal leached in the liquid after leaching, the liquid after leaching is sequentially subjected to multiple stages of solvent extraction or neutralization, etc. according to the metal to be separated. Back extraction, electrolysis, carbonation, and other treatments are performed on each solution obtained in (1). Specifically, each valuable metal can be recovered by first recovering iron and aluminum, then recovering manganese and copper, then cobalt, then nickel, and finally leaving lithium in the aqueous phase. .

As this type of prior art, Patent Document 1 discloses a method for recovering nickel from a sulfuric acid aqueous solution containing nickel, cobalt, iron, aluminum, manganese, and other impurity elements. After removing iron and aluminum by oxidation neutralization treatment, and then separating and recovering the mixed hydroxide containing nickel and cobalt by the neutralization treatment, from the concentrated solution obtained by dissolving the mixed hydroxide, It is described that a back extract containing cobalt and nickel, respectively, is obtained by a solvent extraction process.
Patent Document 2 discloses solvent extraction under predetermined conditions for a metal mixed aqueous solution containing a metal group A composed of lithium, manganese, nickel, and cobalt and a metal group B composed of copper, aluminum, and iron. Are sequentially applied to separate each metal.

JP 2010-180439 A Japanese Patent No. 5706457

As described above, in order to separate and recover each metal from the leached solution containing a plurality of types of metal ions, many processes are required. Therefore, if a specific metal ion can be left as a solid without dissolving it among the multiple types of metal ions contained in the liquid after leaching, the liquid after leaching is used to separate and recover each metal in the subsequent recovery step. Of the various treatments applied to the above, since the treatment necessary for recovering the metal left as a solid can be simplified or omitted, it is effective from the viewpoint of processing efficiency and cost.
In particular, if copper ions are contained in a high concentration in the solution after leaching, for example, it may cause an electrodeposition abnormality in the electrolysis process after solvent extraction of cobalt and back extraction. There is a problem that the load of.

  The object of the present invention is to solve such problems of the prior art, and the object of the present invention is to use as much copper as possible when leaching lithium ion battery scrap containing copper. An object of the present invention is to provide a method for treating lithium ion battery scrap that can be left as a solid without being dissolved in an acidic solution, and can reduce the load in the subsequent process.

As a result of intensive studies, the inventor has suppressed copper oxidative dissolution while cobalt or the like remains as a solid in the acidic solution when the lithium ion battery scrap containing copper is brought into contact with the acidic solution and leached. It was newly found that when cobalt and the like are completely dissolved after that, copper leaching starts and the oxidation-reduction potential rapidly increases accordingly.
And it was thought that by utilizing this, copper can be left as a solid in an acidic solution without dissolving it.

  Based on this knowledge, the lithium ion battery scrap processing method of the present invention has a leaching step of leaching lithium ion battery scrap by bringing a lithium ion battery scrap containing at least copper into contact with an acidic solution, and the leaching step includes Then, at the timing when the oxidation-reduction potential (ORPvsAg / AgCl) of the acidic solution starts to rise rapidly, the metal piece containing at least one element of iron, nickel and cobalt is added to the acidic solution.

  Here, it is preferable that the timing at which the metal piece is added is a period from when the rate of increase of the oxidation-reduction potential becomes 15 mV / min or more until 5 minutes have passed.

According to the method for treating lithium ion battery scrap of the present invention, the leaching solution obtained in the leaching step contains aluminum and iron, and the leaching solution is neutralized within the range of pH 4.0 to 6.0. Liquid separation is performed, and after the leaching, aluminum is removed from the liquid, and after the dealumination process, an oxidizing agent is added to adjust the pH within the range of 3.0 to 5.0 and then solidify. It is preferable to further have a deironing step of performing liquid separation and removing iron.
Here, in the leaching step, the copper contained in the lithium ion battery scrap is left in the liquid after leaching as a solid, and in the dealumination step, the copper in the leached solution is removed together with aluminum by solid-liquid separation. More preferably.

  Further, in the method for treating lithium ion battery scrap of the present invention, the leached liquid obtained in the leaching step contains aluminum and iron, and after performing solid-liquid separation on the leached liquid, an oxidizing agent is added. Then, after adjusting the pH to be in the range of 3.0 to 4.0, solid-liquid separation is performed to remove iron, and after the deironing step, the pH is in the range of 4.0 to 6.0. It is preferable to further include a dealumination step for performing solid-liquid separation after neutralization to remove aluminum.

  The oxidizing agent added in the above-described deironing step is preferably at least one selected from the group consisting of manganese dioxide, a positive electrode active material, and a manganese-containing leaching residue obtained by leaching the positive electrode active material. .

Further, the post-separation liquid obtained through the above-described dealumination process and iron removal process contains manganese, copper, iron and / or aluminum dissolved in the post-separation liquid, and solvent extraction is performed on the post-separation liquid. It is preferable to further have an extraction step of removing manganese, copper, iron and / or aluminum from the separated solution after the separation.
In this extraction step, it is preferable to perform solvent extraction on the post-separation solution using a mixed extract containing a phosphate ester extractant and an oxime extractant.

The lithium ion battery scrap processing method of the present invention preferably further includes a cobalt / nickel recovery step of recovering cobalt and / or nickel from the extraction residual liquid after the extraction step.
It is preferable that the method further includes a lithium recovery step of recovering lithium after the cobalt / nickel recovery step.

  According to the lithium ion battery scrap processing method of the present invention, at the timing when the oxidation-reduction potential of the acidic solution starts to rise rapidly in the leaching step, the metal piece containing at least one element of iron, nickel, and cobalt is added. Since the dissolution of copper is suppressed by adding to the acidic solution, the load in the subsequent process can be reduced by leaving the copper as a solid without dissolving it in the acidic solution as much as possible.

It is a flowchart which shows one Embodiment of the processing method of the lithium ion battery scrap of this invention. It is a flowchart which shows other embodiment of the processing method of the lithium ion battery scrap of this invention. It is a graph which shows the change of ORP, pH, and Cu density | concentration with progress of time in an Example. It is a graph which shows the change of ORP, pH, and Cu density | concentration with progress of time in a comparative example.

Hereinafter, embodiments of the present invention will be described in detail.
In the method for treating lithium ion battery scrap according to one embodiment of the present invention, in the leaching step of leaching the lithium ion battery scrap by bringing the lithium ion battery scrap containing at least copper into contact with the acidic solution and leaching the lithium ion battery scrap, At the timing when the potential (ORPvsAg / AgCl) starts to rise rapidly, a metal piece of at least one element of iron, nickel and cobalt or an alloy containing the at least one element is added to the acidic solution. .

(Lithium ion battery scrap)
The lithium ion battery scrap to be used in the present invention may be any scrap as long as it is a lithium ion battery scrap used in mobile phones and other various electronic devices. From the viewpoint of effective utilization of resources, it is preferable to target products that are discarded due to manufacturing defects or other reasons.

  The lithium ion battery scrap can be a so-called battery case, which may be a mixture of a positive electrode material with an aluminum foil or a positive electrode active material, and the battery case is roasted as necessary. It can be chemically treated, crushed, and / or sieved.

  The battery case includes a positive electrode active material that is a lithium metal salt containing manganese, nickel, and cobalt, a negative electrode material containing carbon, iron, and copper, an aluminum foil to which the positive electrode active material is attached, and aluminum of a lithium ion battery. A case may be included. Specifically, the lithium ion battery includes a single metal oxide composed of one element of lithium, nickel, cobalt, and manganese constituting the positive electrode active material and / or a composite metal oxide composed of two or more elements. As well as aluminum, copper, iron, carbon and the like.

  In this invention, it is particularly effective to target lithium ion battery scrap containing copper in an amount of, for example, 0.5% by mass to 5% by mass, preferably 1% by mass to 15% by mass. When such a relatively large amount of copper-containing lithium ion battery scrap is leached by the conventional method, a solvent extraction is performed on a solution in which a large amount of copper is dissolved. It is because it becomes a cause to generate | occur | produce. In addition, when there is too little copper contained in a lithium ion battery scrap, although it does not become a big problem in particular, the effect by applying this invention becomes thin.

(Leaching process)
In the leaching step, for example, the above-described powdered lithium ion battery scrap obtained by crushing and sieving is brought into contact with an acidic solution such as a sulfuric acid acidic solution as a leaching solution and leached. Thereby, a liquid after leaching in which a predetermined metal contained in the lithium ion battery scrap is leached is obtained.

  In this embodiment, the oxidation-reduction potential (ORPvsAg / AgCl) of the acidic solution charged with the lithium ion battery scrap is measured every few minutes, for example, 0.5 minutes or 0.1 minutes, and the oxidation-reduction is performed. At the timing when the potential starts to rise sharply compared with the change so far, the acid solution contains at least one elemental metal of iron, nickel and cobalt, or an alloy containing the at least one element. Add pieces.

When the acidic solution and the lithium ion battery scrap containing copper are brought into contact with each other, for example, the positive electrode active material cobalt that can be included in the lithium ion battery scrap, aluminum in the aluminum foil, etc. is a base metal than copper. As a result, it is dissolved before copper, and when those metals are completely dissolved, the dissolution of copper starts and the oxidation-reduction potential rises rapidly.
By adding iron, nickel, and / or cobalt to the acidic solution at this timing, those added metals are dissolved instead of copper, so that the dissolution of copper is suppressed and copper is not leached. Here, the oxidation-reduction potential rises rapidly, and after reaching the ORP value at which copper dissolves, the dissolution of copper begins. Even if copper is slightly dissolved before the addition of iron, nickel and / or cobalt, It is believed that copper may return from an ion to a solid as the added iron, nickel and / or cobalt dissolves. In any case, the addition of iron, nickel and / or cobalt contributes to leaving copper as a solid in the post-leaching solution obtained in the leaching step.

  Specifically, the timing of adding the metal piece to the acidic solution is such that after the acidic solution and the lithium ion battery scrap are brought into contact with each other, the increase rate of the oxidation-reduction potential of the acidic solution is 15 mV / min or more, preferably 30 mV / min. Especially when the rate of increase of the oxidation-reduction potential once exceeds 15 mV / min until 5 minutes have passed, preferably until 1 minute has passed. Is preferred. When the rate of increase of the oxidation-reduction potential is less than 15 mV / min, it is considered that cobalt or the like that can be contained in the lithium ion battery scrap is not completely dissolved, and the state before the dissolution of copper has yet started. In addition, there is a concern that a considerable amount of copper is already dissolved after 5 minutes have passed since the rate of increase of the redox potential is 15 mV / min or more.

  More specifically, when the oxidation-reduction potential of the acidic solution is, for example, −300 mV or more and −100 mV or less, preferably −250 mV or more and −200 mV or less, the above-described metal piece is added. Can do. If a metal piece is added in a state where the oxidation-reduction potential is too low, it is considered that cobalt or the like that can be contained in the lithium ion battery scrap is not completely dissolved and copper is not yet dissolved. This is because if the metal piece is added in a state where the reduction potential is too high, there is a concern that copper is already dissolved.

The metal piece added to the acidic solution is a metal containing at least one element of iron, nickel, and cobalt, and it does not matter whether it is made of a single metal or an alloy.
Iron, nickel, and cobalt have a greater ionization tendency than copper, and are easier to dissolve than copper, thereby enabling suppression of copper leaching as described above. In addition, these elements are often contained in lithium ion battery scraps in the first place, and are easily removed or recovered after the leaching process. Aluminum also has a higher ionization tendency than copper and can be included in lithium ion battery scrap, but it is relatively undesirable to remove after the leaching step, so it is less desirable as an additive element to the acidic solution.

  The reason why the above-described element is added to the acidic solution in the form of a metal piece is that recovery by solid-liquid separation or the like in various steps after the leaching step is facilitated. As this metal piece, for example, the maximum dimension is preferably 1 mm to 1000 mm, and more preferably 10 mm to 100 mm. If the metal piece has a size within this range, a contact area with an acidic solution that can be effectively dissolved is ensured, and undissolved material after dissolution can be easily recovered in a subsequent process. When fine powder is used, recovery after the leaching process may require labor or equipment. On the other hand, when a block or block having a certain size is used, the contact area with the acidic solution decreases. Therefore, the dissolution of copper may not be effectively suppressed.

  In the leaching step, the pH of the leaching solution can be 0 to 2.0. If the pH at this time is too high, the leaching rate of cobalt and nickel may not be sufficient. On the other hand, if the pH is too low, the leaching proceeds rapidly and copper is leached, and the post-process This is because there is a possibility that the cost may increase due to pH adjustment when it is necessary to raise the pH.

  In the leaching step, the leaching time from when the lithium ion battery scrap is added to the acidic solution to the end of leaching is preferably 0.5 hours to 10 hours. If the reaction time is too short, cobalt or nickel to be dissolved may not be sufficiently dissolved. On the other hand, if the leaching time is too long, dissolution of copper may start. A more preferable range of the leaching time is 1 hour to 5 hours, more preferably 1 hour to 3 hours.

  After the leaching process described above, for example, the process of the embodiment shown in FIG. 1 or the embodiment shown in FIG. 2 can be performed. Each embodiment will be described in detail below.

<Embodiment shown in FIG. 1>
In the embodiment shown in FIG. 1, after the leaching step, the dealumination step and the iron removal step are performed in this order, and then the cobalt / nickel recovery step and the lithium recovery step are performed through the extraction step.

(Dealuminizing process)
In the dealumination step, the pH of the leached solution obtained in the leaching step is neutralized by raising the pH in the range of 4.0 to 6.0, thereby precipitating aluminum in the leached solution, The aluminum is removed by subsequent solid-liquid separation.

In this dealumination step, if the pH is too low, the aluminum cannot be sufficiently precipitated. On the other hand, if the pH is too high, other metals such as cobalt are also precipitated. From this viewpoint, the pH of the solution after leaching in the dealumination process is more preferably 4.0 to 6.0, and particularly preferably 4.5 to 5.0.
In the dealumination step, in order to raise the pH within the above-described range, for example, alkali such as sodium hydroxide, sodium carbonate, ammonia or the like can be added to the liquid after leaching.

In the dealumination step, the redox potential (ORPvsAg / AgCl) of the solution after leaching is preferably −500 mV to 100 mV, and more preferably −400 mV to 0 mV. If the oxidation-reduction potential at this time is too high, cobalt may precipitate as tricobalt tetroxide (Co ₃ O ₄ ). On the other hand, if the oxidation-reduction potential is too low, cobalt is a single metal (Co metal). ) To be precipitated.

  In the dealumination step, it is preferable that the temperature of the leached solution is 50 ° C to 90 ° C. In other words, if the temperature of the liquid after leaching is less than 50 ° C, there is a concern that the reactivity will deteriorate, and if it is higher than 90 ° C, a device that can withstand high heat is required. Is also not preferred.

After sufficiently precipitating aluminum as described above, solid-liquid separation is performed using a known apparatus and method such as a filter press or thickener to mainly remove the precipitated aluminum.
In the solid-liquid separation in the dealumination process, the copper remaining as a solid without being dissolved in the leaching process and the carbon that can be contained in the lithium ion battery scrap can also be separated. In this solid-liquid separation, since copper can be removed together with aluminum, for example, solid-liquid separation for removing copper alone immediately after the leaching step can be omitted, thereby improving the processing efficiency and reducing the cost. it can. Therefore, it is preferable to leave the copper in the liquid after leaching as a solid without performing solid-liquid separation after the leaching process and before the dealumination process.

  In addition, if an aluminum-only precipitate is filtered, it is difficult to filter the gel-like aluminum precipitate, resulting in a decrease in the filtration rate, but in the solid-liquid separation in this dealumination step, Since not only aluminum but also copper, carbon, and the like are included, such copper, carbon, etc. can compensate for the difficulty of filtering the gel-like aluminum precipitate, and the time required for filtration can be shortened.

Note that the liquid after leaching obtained in the leaching step described above contains lithium dissolved therein, and the molar ratio of lithium to aluminum (Li / Al ratio) in the liquid after leaching is 1.1 or more. For example, the aluminum contained in the precipitate in the dealumination step produces gel-like Al (OH) ₃ as well as complex oxides and hydroxides such as crystalline LiAlO ₂ and LiAl ₂ (OH) _7. And it becomes a form close to powder. In this case, the filtration time can be further shortened. From this viewpoint, the molar ratio of lithium to aluminum (Li / Al ratio) in the liquid after leaching is preferably 1.1 or more.

  In addition, the lithium in the solution after leaching can be obtained by acid leaching of lithium originally contained in the lithium ion battery scrap, and other lithium-containing materials are added to the solution after leaching, and this is acid leached. It can also be Moreover, it is possible to adjust the Al / Li ratio in the liquid after leaching by adding a lithium-containing material. As the lithium-containing material, a reagent can be used, but lithium carbonate, lithium hydroxide and other lithium compounds obtained in the lithium ion battery scrap treatment process, or at least one of them can be dissolved in water. It is preferable to obtain an obtained lithium aqueous solution.

(Deironing process)
In the iron removal step, an oxidant is added to the solution obtained in the above dealumination step, and the pH in the range of 3.0 to 5.0 is adjusted to precipitate iron in the solution, The iron is removed by subsequent solid-liquid separation.

In this iron removal step, the iron in the solution is oxidized from divalent to trivalent by the addition of an oxidizing agent, and the trivalent iron is oxidized (hydroxylated) at a lower pH than divalent iron. Therefore, iron can be precipitated by adjusting to a relatively low pH as described above. In many cases, iron precipitates as a solid such as iron hydroxide (Fe (OH) ₃ ).
Here, if the pH is greatly increased, precipitation of cobalt is caused. However, in this deironing step, iron can be precipitated without significantly increasing the pH. It can be effectively suppressed.

  In the iron removal step, if the pH is too low, iron cannot be sufficiently precipitated. On the other hand, if the pH is too high, other metals such as cobalt are also precipitated. From this viewpoint, the pH in the iron removal step is more preferably 3.0 to 4.0, and particularly preferably 3.0 to 3.5.

  In the iron removal step, the redox potential (ORPvsAg / AgCl) of the solution is preferably 300 mV to 900 mV, more preferably 500 mV to 700 mV. If the redox potential at this time is too low, iron may not be oxidized. On the other hand, if the redox potential is too high, cobalt may be oxidized and precipitated as an oxide.

  In the iron removal step, prior to the addition of the oxidizing agent, for example, an acid such as sulfuric acid, hydrochloric acid, or nitric acid can be added in order to lower the pH to the above-described range.

The oxidizing agent added in the deironing step is not particularly limited as long as it can oxidize iron, but it should be a manganese-containing leaching residue obtained by leaching manganese dioxide, a positive electrode active material, and / or a positive electrode active material. Is preferred. These can effectively oxidize iron in solution. The manganese-containing leaching residue obtained by leaching the positive electrode active material with an acid or the like may contain manganese dioxide.
When the above positive electrode active material or the like is used as the oxidizing agent, a precipitation reaction occurs in which manganese dissolved in the solution becomes manganese dioxide, so that the precipitated manganese can be removed together with iron.

  After the addition of the oxidizing agent, the pH can be adjusted to a predetermined range by adding an alkali such as sodium hydroxide, sodium carbonate, ammonia or the like.

(Extraction process)
When manganese is contained in the liquid after separation and iron removal process due to the inclusion of manganese in the lithium ion battery scrap, etc., or completely in the leaching process, aluminum removal process, and iron removal process described above. In some cases, the post-separation liquid contains copper, aluminum, and iron that remain without being removed. In this case, an extraction step of extracting manganese or the like from the post-separation liquid can be performed. However, this extraction step can be omitted if the separated liquid does not contain manganese or the like.

Specifically, in the extraction process, solvent extraction using a mixed extract containing a phosphate ester extractant and an oxime extractant is performed on the post-separation liquid after the iron removal process, and manganese, copper, iron And / or aluminum can be separated.
In particular, the combined use of a phosphate ester extractant and an oxime extractant significantly improves the separation efficiency of copper, iron, and aluminum. Among them, almost all copper can be extracted.

(Cobalt / nickel recovery process)
After the manganese extraction step, cobalt and / or nickel in the extraction residue is recovered. Cobalt and / or nickel can be recovered by a known method. Specifically, cobalt and nickel are sequentially extracted by solvent, cobalt in the solvent is transferred to the aqueous phase by back extraction and recovered by electrowinning, and nickel in the solvent is similarly back extracted and electrolyzed. It can be recovered by sampling.

(Lithium recovery process)
If lithium remains after the cobalt / nickel recovery step, the aqueous phase lithium can be carbonated and recovered as lithium carbonate, for example.

<Embodiment shown in FIG. 2>
In the embodiment shown in FIG. 2, after the above leaching step, the iron removal step and the dealumination step are performed in this order, contrary to the embodiment shown in FIG. 1, and then the same as the embodiment shown in FIG. 1. Then, after the extraction process, a cobalt / nickel recovery process and a lithium recovery process are performed.
In the embodiment shown in FIG. 2, at the end of the above leaching step, the liquid after leaching is subjected to solid-liquid separation using a known apparatus and method such as a filter press or thickener, and the copper contained in the liquid after leaching. Etc. can be removed.

(Deironing process)
After the solid-liquid separation in the leaching step, as a deironing step, an oxidant is added and the pH is adjusted within the range of 3.0 to 4.0 to precipitate iron in the solution. Such iron is removed by liquid separation.
In this iron removal step, the iron in the solution is oxidized from divalent to trivalent by the addition of an oxidizing agent, and the trivalent iron precipitates as an oxide (hydroxide) at a lower pH than the divalent iron. Therefore, iron can be precipitated by adjusting to a relatively low pH as described above. In many cases, iron precipitates as a solid such as iron hydroxide (Fe (OH) ₃ ).
When the pH is greatly increased, precipitation of cobalt is caused, but in this deironing step, iron can be precipitated without increasing the pH so much, so that the precipitation of cobalt at this time is effectively suppressed. be able to.

  In the iron removal step, if the pH is too low, iron cannot be sufficiently precipitated. On the other hand, if the pH is too high, other metals such as cobalt are also precipitated. From this viewpoint, the pH in the iron removal step is more preferably 3.0 to 4.0.

  In the iron removal step, the redox potential (ORPvsAg / AgCl) of the solution is preferably 500 mV to 1400 mV, more preferably 700 mV to 1200 mV. If the oxidation-reduction potential at this time is too high, cobalt may be oxidized and precipitate as an oxide. On the other hand, if the oxidation-reduction potential is too low, iron may not be oxidized.

The oxidizing agent added in the deironing step is not particularly limited as long as it can oxidize iron, but it should be a manganese-containing leaching residue obtained by leaching manganese dioxide, a positive electrode active material, and / or a positive electrode active material. Is preferred. These can effectively oxidize iron in solution. The manganese-containing leaching residue obtained by leaching the positive electrode active material with an acid or the like may contain manganese dioxide.
In addition, when using said positive electrode active material as an oxidizing agent, since the precipitation reaction from which the manganese melt | dissolved in the solution turns into manganese dioxide arises, the precipitated manganese can be removed with iron.

  Moreover, in the iron removal process, in order to adjust pH to the range mentioned above, alkalis, such as sodium hydroxide, sodium carbonate, ammonia, can be added, for example.

(Dealuminizing process)
In the dealumination process, the pH of the solution obtained in the dealumination process is raised to 4.0 to 6.0 to neutralize the solution, thereby precipitating aluminum in the solution. Such aluminum is removed by solid-liquid separation.

In this dealumination step, if the pH is too low, aluminum cannot be sufficiently precipitated. On the other hand, if the pH is too high, other metals such as cobalt are also precipitated. From this viewpoint, the pH in the dealumination process is more preferably 4.0 to 6.0, and particularly preferably 4.5 to 5.0.
In the dealumination step, for example, an alkali such as sodium hydroxide, sodium carbonate, or ammonia can be added in order to raise the pH within the above-described range.

  In the dealumination process, it is preferable that the temperature of the solution is 60 ° C to 90 ° C. That is, if the temperature is less than 60 ° C., there is a concern that the reactivity may deteriorate, and if it is higher than 90 ° C., a device that can withstand high heat is required and it is not preferable for safety. . Therefore, the temperature of the solution is preferably 60 ° C to 90 ° C.

Here, when the leached liquid obtained in the leaching step described above contains dissolved lithium, the molar ratio of lithium to aluminum in the leached liquid (Li / Al ratio) should be 1.1 or more. This is preferable in terms of improving the filterability of the precipitate in the dealumination step. In this case, the aluminum contained in the precipitate in the dealumination step is not only gel-like Al (OH) ₃ but also complex oxides such as crystalline LiAlO ₂ and LiAl ₂ (OH) ₇ and composite hydroxides. Since this precipitate which is generated and has a form close to powder is easy to filter during solid-liquid separation, the time required for filtration during solid-liquid separation in the dealumination process can be shortened.
From this viewpoint, the molar ratio of lithium to aluminum (Li / Al ratio) in the liquid after leaching is preferably 1.1 or more.

  In addition, the lithium in the solution after leaching can be obtained by acid leaching of lithium originally contained in the lithium ion battery scrap. It can also be made. Moreover, it is possible to adjust the Al / Li ratio in the liquid after leaching by adding a lithium-containing material. As the lithium-containing material, a reagent can be used, but lithium carbonate, lithium hydroxide and other lithium compounds obtained in the lithium ion battery scrap treatment process, or at least one of them can be dissolved in water. It is preferable to obtain an obtained lithium aqueous solution.

(Extraction process)
If manganese is contained in the liquid after separation after the iron removal process and the dealumination process due to the inclusion of manganese in the lithium ion battery scrap, etc., or if the leaching process, the iron removal process, and the dealumination process are complete. In some cases, copper, iron, and aluminum remaining without being removed are contained in the post-separation liquid. In this case, an extraction step of extracting manganese or the like from the post-separation liquid can be performed. However, this extraction step can be omitted when the separation liquid does not contain manganese or the like.

Specifically, in the extraction step, the separated liquid after the dealumination step is subjected to solvent extraction using a mixed extractant containing a phosphate ester type extractant and an oxime type extractant, and manganese, copper, iron And / or aluminum can be separated.
In particular, the combined use of a phosphate ester extractant and an oxime extractant significantly improves the separation efficiency of copper, iron, and aluminum. Among them, almost all copper can be extracted.

(Cobalt / nickel recovery process)
After the manganese extraction step, cobalt and / or nickel in the extraction residue is recovered. Cobalt and / or nickel can be recovered by a known method. Specifically, cobalt and nickel are sequentially extracted by solvent, cobalt in the solvent is transferred to the aqueous phase by back extraction and recovered by electrowinning, and nickel in the solvent is similarly back extracted and electrolyzed. It can be recovered by sampling.

(Lithium recovery process)
If lithium remains after the cobalt / nickel recovery step, the aqueous phase lithium can be carbonated and recovered as lithium carbonate, for example.

  Next, the present invention was experimentally implemented and its effects were confirmed, and will be described below. However, the description here is for illustrative purposes only and is not intended to be limiting.

  After charging 41.1 g of battery powder of the grade shown in Table 1 as lithium-ion battery scrap into pure water and stirring at a speed of 500 rpm, 98% concentrated sulfuric acid was added to a pH of 1.8, thereby The resulting acidic solution was warmed to 70 ° C.

Stirring was continued at 70 ° C. until the ORP of the acidic solution became −250 mV (Ag / AgCl), and concentrated sulfuric acid was appropriately added so that the pH was maintained at 1.8 during this time.
In the examples, when the ORP of the acidic solution reached −250 mV, 0.5 g of Co metal piece was added to the acidic solution, and stirring was continued at 70 ° C. for 30 minutes after the addition. On the other hand, in the comparative example, stirring was continued at 70 ° C. for 30 minutes after the ORP of the acidic solution became −250 mV without adding the metal piece.

Changes in ORP, pH, and Cu concentration over time in each of these examples and comparative examples are shown graphically in FIGS. 3 and 4, respectively. Moreover, the measured value of those ORP, pH, and Cu density | concentration in each of an Example and a comparative example is shown in Table 2 and Table 3, respectively with an ORP raise rate.
Here, the time when the liquid temperature reached 70 ° C. was defined as time 0 h.

  In the example, as shown in FIG. 3, the Cu concentration in the acidic solution could be kept low by adding the metal piece at the timing when the ORP rapidly increased. On the other hand, in the comparative example, as shown in FIG. 4, the Cu concentration was greatly increased by not adding the metal piece.

  From the above test results, it was found that according to the present invention, copper can be left as a solid without being dissolved in an acidic solution in the leaching step, thereby contributing to the reduction of the load in the subsequent step.

Claims (10)

Contacting a lithium ion battery scrap containing at least copper with an acidic solution and leaching the lithium ion battery scrap;
In the leaching step, at the timing when the oxidation-reduction potential (ORPvsAg / AgCl) of the acidic solution starts to rise rapidly, a metal piece containing at least one element of iron, nickel, and cobalt is added to the acidic solution. Ion battery scrap processing method.   The method for treating lithium ion battery scrap according to claim 1, wherein the timing of adding the metal piece is from when the rate of increase of the oxidation-reduction potential becomes 15 mV / min or more until 5 minutes elapses. The leached liquid obtained in the leaching step contains aluminum and iron,
After the leaching solution is neutralized within the range of pH 4.0 to 6.0, solid-liquid separation is performed, and a dealumination step of removing aluminum in the solution after leaching, and after the dealumination step, an oxidizing agent The lithium-ion battery according to claim 1, further comprising a step of removing iron by performing solid-liquid separation after adding pH and adjusting the pH within a range of 3.0 to 5.0. Scrap processing method.   In the leaching step, the copper contained in the lithium ion battery scrap is left in the liquid after leaching in the solid state, and in the dealumination step, the copper in the liquid after leaching is removed together with aluminum by solid-liquid separation. Item 4. A method for treating lithium-ion battery scraps according to Item 3. The leached liquid obtained in the leaching step contains aluminum and iron,
After the leaching, solid-liquid separation is performed, and then an oxidant is added to adjust the pH within the range of 3.0 to 4.0, followed by solid-liquid separation to remove iron. The method according to claim 1, further comprising: a step and a dealumination step of removing aluminum by performing solid-liquid separation after neutralization within the range of pH 4.0 to 6.0 after the iron removal step. Lithium ion battery scrap processing method.   The oxidizing agent added in the iron removal step is at least one selected from the group consisting of manganese dioxide, a positive electrode active material, and a manganese-containing leaching residue obtained by leaching the positive electrode active material. The processing method of the lithium ion battery scrap as described in any one of these. The separated liquid obtained through the dealumination step and the iron removal step contains manganese, copper, iron and / or aluminum dissolved in the solution after separation,
The lithium ion according to any one of claims 3 to 6, further comprising an extraction step of performing solvent extraction on the post-separation liquid and removing manganese, copper, iron and / or aluminum from the post-separation liquid. Battery scrap processing method.   The processing method of the lithium ion battery scrap of Claim 7 which carries out solvent extraction using the mixed extract containing a phosphate ester type extractant and an oxime type extractant with respect to the said separated liquid at the said extraction process.   The processing method of the lithium ion battery scrap of Claim 8 which further includes the cobalt / nickel collection | recovery process which collect | recovers cobalt and / or nickel from the extraction residual liquid after the said extraction process.   The method for processing lithium ion battery scrap according to claim 9, further comprising a lithium recovery step of recovering lithium after the cobalt / nickel recovery step.